KR102520047B1 - Light-emitting device, integrated light-emitting device and light-emitting module - Google Patents

Abstract

[Problem] To provide a light emitting device in which luminance unevenness is suppressed.
[Solution] A light emitting device comprises a base body 10 having conductor wiring, a light emitting element 21 disposed on the base body so as to be electrically connected to the conductor wiring, and a dielectric multilayer film provided on an upper surface 21a of the light emitting element 21. (22), and the dielectric multilayer film 22 has a spectral reflectance of 10 in a region 50 nm longer wavelength than the emission peak wavelength region of the light emitting element with respect to the spectral reflectance in the emission peak wavelength region of the light emitting element. greater than %

Description

Light emitting device, integrated light emitting device and light emitting module

The present disclosure relates to light emitting devices, integrated light emitting devices, and light emitting modules.

[0002] In recent years, direct type surface light emitting devices using semiconductor light emitting elements have been proposed as backlights used in display devices such as liquid crystal display devices. From the viewpoints of functionality, design, etc., display devices are sometimes required to be thin, and backlights are also required to be thinner. In addition, even in a light emitting device for general lighting, there are cases where a thin shape is required from the viewpoint of functionality, design, and the like.

When a light emitting device for such a purpose is reduced in thickness, uneven luminance generally tends to occur on the light emitting surface. In particular, when a plurality of light-emitting elements are arranged one-dimensionally or two-dimensionally, the luminance immediately above the light-emitting element is higher than that of the surrounding area. For this reason, for example, Patent Literature 1 encapsulates the light emitting element and partially disposes a diffusion member near the region directly above the light emitting element as the surface of a resin body functioning as a lens to emit light from a light source. A technique for increasing the uniformity of light is disclosed.

International Publication No. 2012/099145

The present disclosure provides a light emitting device in which luminance unevenness is suppressed.

A light emitting device of the present disclosure includes a base having conductor wiring, a light emitting element disposed on the base so as to be electrically connected to the conductor wiring, and a dielectric multilayer film provided on an upper surface of the light emitting element, wherein the light emission peak of the light emitting element Regarding the spectral reflectance in the wavelength region, the spectral reflectance in the region on the 50 nm long wavelength side is greater than the emission peak wavelength region of the light emitting element by 10% or more.

According to the present disclosure, there is provided a light emitting device with wide light distribution in which luminance unevenness between a region above a light emitting element and a region around the light emitting element is suppressed.

1 is a cross-sectional view showing an example of a light emitting device according to a first embodiment.
FIG. 2 is a diagram showing an example of the spectral reflection characteristics of the dielectric multilayer film of the light emitting device shown in FIG. 1 .
Fig. 3 is a diagram showing a state of light emission viewed through a diffusion plate in which a general dielectric multilayer film is provided on the upper surface of a light emitting element.
4 is a diagram showing the incidence angle dependence of spectral reflection characteristics of a dielectric multilayer film.
FIG. 5 is a schematic diagram showing a state of light emitted from a light emitting element in the light emitting device shown in FIG. 1 .
6A is a cross-sectional view showing an example of a light emitting module according to a second embodiment.
Fig. 6B is a top view of an integrated light emitting device in the light emitting module shown in Fig. 6A.
7A is a cross-sectional view showing an example of a backlight according to a third embodiment.
7B is a cross-sectional view showing another example of the backlight of the third embodiment.

Hereinafter, embodiments of a light emitting device, an integrated type light emitting device, and a light emitting module according to the present disclosure will be described with reference to the drawings. The light emitting device, integrated type light emitting device, and light emitting module described below are examples of embodiments, and various modifications are possible in the form described in the embodiments. In the following description, terms indicating a specific direction or position (for example, "top", "bottom", "left", "right" and other terms including these terms) may be used. These terms are only used to indicate relative directions or positions in the referenced drawings in an easy-to-understand manner. As long as the relative direction or positional relationship according to terms such as "upper" and "lower" in the referenced drawings is the same, in drawings other than the present disclosure, actual products, etc., the arrangement may not be the same as the referenced drawings. In addition, the sizes and positional relationships of components shown in the drawings are exaggerated in some cases for ease of understanding, so the size of an actual light emitting device or the size of components in an actual light emitting device. There are cases in which the relationship is not strictly reflected. In addition, in order to avoid making the drawing excessively complicated, illustration of some elements may be omitted in a schematic cross-sectional view or the like.

(First Embodiment)

1 is a schematic diagram showing a cross-sectional structure of a light emitting device 101 according to this embodiment. The light emitting device 101 includes a base 10 , a light emitting element 21 , and a dielectric multilayer film 22 . Hereinafter, each component will be described in detail.

[gas (10)]

The body 10 has an upper surface and supports the light emitting element 21 . In addition, the base body 10 supplies power to the light emitting element 21 . The base 10 includes, for example, a base 11 and conductor wiring 12 . The base 10 may further include an insulating layer 13 .

The substrate 11 is made of, for example, resins such as phenol resin, epoxy resin, polyimide resin, BT resin, polyphthalamide (PPA), and polyethylene terephthalate (PET), ceramics, or the like. Among them, it is preferable to select a resin having insulating properties from the viewpoint of low cost and ease of molding. Alternatively, ceramics may be selected as the material of the substrate 11 in order to realize a light emitting device having excellent heat resistance and light resistance. Examples of ceramics include alumina, mullite, forsterite, glass ceramics, nitride-based (eg, AlN), carbide-based (eg, SiC), and the like. Among them, ceramics containing alumina or containing alumina as a main component are preferred.

In addition, when resin is used as the material constituting the substrate 11, inorganic fillers such as glass fibers, SiO ₂ , TiO ₂ , and Al ₂ O ₃ are mixed with the resin to improve mechanical strength, reduce thermal expansion, Improvement of reflectance and the like can also be aimed at. In addition, the substrate 11 may be a composite plate in which an insulating layer is formed on a metal plate.

The conductor wiring 12 has a predetermined wiring pattern. The conductor wiring 12 is electrically connected to the electrode of the light emitting element 21 and supplies electric power from the outside to the light emitting element 21 . The wiring pattern includes a positive electrode wiring connected to the positive electrode of the light emitting element 21 and a negative electrode wiring connected to the negative electrode of the light emitting element 21 . The conductor wiring 12 is formed on at least the upper surface of the base 10, which serves as the mounting surface of the light emitting element 21. The material of the conductor wiring 12 can be appropriately selected from among conductive materials depending on the material of the substrate 11, the manufacturing method of the substrate 11, and the like. For example, when ceramics is used as the material of the substrate 11, the material of the conductor wiring 12 is preferably a material having a high melting point that can withstand the firing temperature of the ceramic sheet. For example, tungsten, It is preferable to use a metal with a high melting point such as molybdenum. A layer of another metal material such as nickel, gold, or silver may be further provided on the wiring pattern made of the above-mentioned high-melting point metal by plating, sputtering, vapor deposition, or the like.

When using resin as the material of the substrate 11, the material of the conductor wiring 12 is preferably a material that is easy to process. In the case of using an injection-molded resin, the material of the conductor wiring 12 is preferably a material that can be easily punched, etched, or bent, and has relatively high mechanical strength. Specifically, metals such as copper, aluminum, gold, silver, tungsten, iron, and nickel, or metal layers or lead frames such as iron-nickel alloys, phosphor bronze, copper-iron alloys, and molybdenum It is preferable that the conductor wiring 12 is formed. The conductor wiring 12 may further include a layer of another metal material on the surface of the wiring pattern made of these metals. Although this material is not particularly limited, for example, a layer made of only silver or an alloy of silver and copper, gold, aluminum, rhodium, or the like, or a multilayer using these, silver or each alloy can be used. A layer made of another metal material can be formed by plating, sputtering, vapor deposition, or the like.

[Insulation layer 13]

The base body 10 may include an insulating layer 13 . The insulating layer 13 covers a portion of the conductor wiring 12 of the base 10 to which the light emitting element 21 or the like is connected and is provided on the base 11 . That is, the insulating layer 13 has electrical insulating properties and covers at least a part of the conductor wiring 12 . Preferably, the insulating layer 13 has light reflectivity. Since the insulating layer 13 has light reflectivity, light emitted from the light emitting element 21 toward the base body 10 can be reflected, and the light extraction efficiency can be improved. In addition, since the insulating layer 13 has light reflectivity, among the light emitted from the light source and impinging on the light-transmitting laminate including the diffuser plate and the wavelength conversion member, for example, the reflected light is also reflected, thereby improving the light extraction efficiency. can improve By transmitting the light reflected by these substrates through the light-transmitting laminate, uneven brightness can be further suppressed.

The material of the insulating layer 13 is not particularly limited as long as it absorbs little light emitted from the light emitting element 21 and has insulating properties. For example, resin materials such as epoxy, silicone, modified silicone, urethane resin, oxetane resin, acrylic, polycarbonate, and polyimide can be used. In the case of imparting light reflectivity to the insulating layer 13, the insulating layer 13 may contain a white filler added to an underfill material described later in the resin material described above. The white filler is explained in detail below.

[Light emitting element 21]

For the light emitting element 21 disposed on the body 10, various types of light emitting elements can be used. The light emitting element 21 is a light emitting diode in this embodiment. The wavelength of light emitted from the light emitting element 21 can be arbitrarily selected. For example, as a blue or green light emitting element, light emission using semiconductors such as nitride-based semiconductors (In _x Al _y Ga _{1 -x- y} N, 0≤X, 0≤Y, X+Y≤1), ZnSe, and GaP element can be used. As the red light emitting element, a light emitting element using a semiconductor such as GaAlAs or AlInGaP can be used. In addition, a semiconductor light emitting element made of other materials can also be used. The composition, emission color, size, number, and the like of the light-emitting elements to be used can be appropriately selected according to the purpose.

When the light emitting element 21 includes a wavelength conversion member, the light emitting element 21 emits short-wavelength light capable of efficiently exciting the wavelength conversion material included in the wavelength conversion member (In _x Al _y Ga _{1 -x- y} N, 0≤X, 0≤Y, X+Y≤1) is preferably used. Depending on the material of the semiconductor layer and the degree of mixing, various emission wavelengths can be selected. The light emitting element 21 may have a positive electrode and a negative electrode on the same surface side, or may have a positive electrode and a negative electrode on different surfaces.

The light emitting element 21 has, for example, a substrate for growth and a semiconductor layer laminated on the substrate for growth. The semiconductor layer includes an n-type semiconductor layer, a p-type semiconductor layer, and an active layer sandwiched therebetween. A negative electrode and a positive electrode are electrically connected to the n-type semiconductor layer and the p-type semiconductor layer, respectively. As the substrate for growth, for example, a translucent sapphire substrate or the like can be used.

The n-side electrode and the p-side electrode of the light emitting element 21 are flip-chip mounted on the base body 10 via a connecting member 23 . Specifically, the positive electrode and the negative electrode of the light emitting element 21 are connected to the positive electrode wiring and the negative electrode wiring included in the conductor wiring 12 of the base body 10 by a connecting member 23 . The surface opposite to the surface on which the n- and p-electrodes of the light emitting element 21 are formed, that is, the upper surface 21a, which is the main surface of the translucent sapphire substrate, serves as the light extraction surface. In this embodiment, in order to reduce the luminance right above the light emitting element 21, a dielectric multilayer film 22 is disposed on the upper surface 21a. For this reason, the side surface 21c of the light emitting element 21 also serves as a substantial light extraction surface.

[connection member (23)]

The connecting member 23 is formed of a conductive material. Specifically, the material of the connecting member 23 is Au-containing alloy, Ag-containing alloy, Pd-containing alloy, In-containing alloy, Pb-Pd-containing alloy, Au-Ga-containing alloy, Au-Sn-containing alloy, Sn-containing alloy, Sn-Cu-containing alloys, Sn-Cu-Ag-containing alloys, Au-Ge-containing alloys, Au-Si-containing alloys, Al-containing alloys, Cu-In-containing alloys, mixtures of metals and fluxes, and the like.

As the connection member 23, a liquid, paste, or solid (sheet, block, powder, or wire shape) can be used, and can be appropriately selected according to the composition or shape of the support. In addition, these connection members 23 may be formed as a single member, or may be used in combination of several types.

[Underfill member 24]

An underfill member 24 may be disposed between the light emitting element 21 and the base body 10 . The underfill member 24 contains a filler for the purpose of efficiently reflecting light from the light emitting element 21 and bringing the coefficient of thermal expansion closer to that of the light emitting element 21 . As shown in FIG. 1 , the underfill member 24 preferably does not cover the side surface 21c of the light emitting element 21 since the side surface 21c of the light emitting element 21 is also a light extraction surface in this embodiment.

The underfill member 24 includes, as a base material, a material that absorbs little light from the light emitting element. For example, epoxy, silicone, modified silicone, urethane resin, oxetane resin, acrylic, polycarbonate, polyimide or the like can be used.

If the filler of the underfill member 24 is a white filler, light is more easily reflected and the light extraction efficiency can be improved. Moreover, it is preferable to use an inorganic compound as a filler. The term "white" here includes what appears white due to scattering when there is a difference in refractive index from the material around the filler even when the filler itself is transparent.

The reflectance of the filler is preferably 50% or more, and more preferably 70% or more with respect to light of the light emission wavelength of the light emitting element 21. Accordingly, the light extraction efficiency of the light emitting device 101 can be improved. Moreover, as for the particle size of a filler, 1 nm or more and 10 micrometers or less are preferable. By setting the particle size of the filler within this range, the fluidity of the resin as an underfill material is improved, and the material used as the underfill member 24 can be satisfactorily filled even in a narrow gap. In addition, the particle size of the filler is preferably 100 nm or more and 5 μm or less, more preferably 200 nm or more and 2 μm or less. In addition, the shape of the filler may be spherical or scaly.

As the filler material, specifically, SiO ₂ , Al ₂ O ₃ , Al(OH) ₃ , MgCO ₃ , TiO ₂ , ZrO ₂ , ZnO, Nb ₂ O ₅ , MgO, Mg(OH) ₂ , SrO, In ₂ oxides such as O ₃ , TaO ₂ , HfO, SeO, and Y ₂ O ₃ ; nitrides such as SiN, AlN, and AlON; and fluorides such as MgF ₂ . These may be used individually or may be used in mixture.

[Dielectric multilayer film 22]

The dielectric multilayer film 22 reflects part of incident light and transmits part of it (for example, a half mirror), and is provided on the upper surface 21a of the light emitting element 21 . With this configuration, part of the light emitted from the upper surface 21a of the light emitting element 21 is reflected by the dielectric multilayer film 22, returns to the light emitting element 21, and passes through the side surface 21c of the light emitting element 21. go out As a result, when the amount of light emitted from the upper surface 21a of the light emitting element 21 is reduced and the luminance above the light emitting element 21 is reduced, a backlight or the like is configured using the light emitting device 101. Suppresses luminance unevenness in However, as will be described later, if a dielectric multilayer film having general spectral reflection characteristics is provided on the upper surface 21a of the light emitting element 21, when the light emitted from the light emitting device 101 is observed through the diffusion plate, When the distance between the diffusion plate and the light emitting element is shortened, the luminance of the area around the light emitting element is higher than that of the area immediately above the light emitting element. That is, luminance unevenness tends to occur.

In order to suppress such luminance unevenness, the dielectric multilayer film 22 has spectral reflectance characteristics including at least two regions having different spectral reflectances in the reflection wavelength band. 2, a typical example of the spectral reflectance characteristics of the dielectric multilayer film 22 is shown by a solid line. A schematic example of the emission spectrum of light emitted from the light emitting element 21 is also shown.

In the dielectric multilayer film 22, the spectral reflectance in the emission peak wavelength region (R _E ) of the light emitting element 21 is 50 nm longer wavelength than the emission peak wavelength region of the light emitting element 21 (R _L ) The spectral reflectance in has a spectral reflectance characteristic of 10% or more. Here, the spectral reflectance is a value for normally incident light. Note that the emission peak wavelength region (R _E ) is a wavelength region of a predetermined width centered on the peak wavelength λp of the light emitting element 21 . For example, it is a wavelength range of λE1 or more and λE2 or less (λE1 < λE2). The band of the emission peak wavelength region (R _E ) is determined according to the characteristics of light emitted from the light emitting element 21 . For example, when the light emitting element 21 is an LED that emits blue light, the band of the emission peak wavelength region (R _E ) may be λp±20 nm.

Further, the region R _L is a region including a region in which the upper and lower limits of the emission peak wavelength region R _E are the upper and lower limits of the wavelength on the long-wavelength side of 50 nm, respectively. Specifically, the region R _L is a wavelength region of (λE1+50) nm or more and (λE2+50) nm or less. In addition, with respect to the spectral reflectance in the emission peak wavelength region (R _E ), the fact that the spectral reflectance in the region (R _L ) is greater than 10% means the maximum spectral reflectance in the emission peak wavelength region (R _E ). , it means that the spectral reflectance at any wavelength within the region R _L is greater than 10%. In addition, the spectral reflectance in the emission peak wavelength region R _E is 70% or more and 95% or less, and the spectral reflectance in the region R _L is 80% or more and less than 100%. The emission peak wavelength region (R _E ) and region (R _L ) do not overlap each other.

The reflection wavelength band (B) at normal incidence is defined as a region including the above-described emission peak wavelength region (R _E ) and region (R _L ) and having a spectral reflectance of 50% or more. The reflection wavelength band B of the dielectric multilayer film 22 includes the emission peak wavelength of the light emitting element, and the longer wavelength side ( _BL ) is wider than the short wavelength side ( _BS ) than the emission peak wavelength.

The dielectric multilayer film 22 has a dielectric multilayer structure in which a plurality of dielectric layers having light transmission properties and different refractive indices are laminated. As a specific material for the dielectric layer, a material having low light absorption in the wavelength region emitted from the light emitting element 21, such as a metal oxide film, a metal nitride film, a metal fluoride film, or an organic material, is preferable. Moreover, as a dielectric layer, you may use organic layers, such as a silicone resin and a fluororesin.

The spectral reflectance characteristics of the dielectric multilayer film 22, specifically, the position of the emission peak wavelength region (R _E ) and the region (R _L ), the spectral reflectance, etc., are arbitrarily determined by adjusting the thickness, refractive index, number of layers, etc. of the dielectric layer. it is possible to set In addition, it is possible to separately design the spectral reflectance of the emission peak wavelength region (R _E ) and the region (R _L ).

[Encapsulating member 30]

The light emitting device 101 may include a sealing member 30 . The sealing member 30 protects the light emitting element 21 from the external environment and optically controls the light distribution characteristics of light output from the light emitting element 21 . That is, the emission direction of light is mainly controlled by refraction of light on the outer surface of the sealing member 30 . The sealing member 30 covers the light emitting element 21 and is disposed on the base 10 .

The surface of the sealing member 30 has a convex curved surface. When viewed from above, the sealing member 30 preferably has a circular or elliptical outer shape. In the sealing member 30, it is preferable that the ratio H/W of the height H in the optical axis L direction and the width W when viewed from above is smaller than 0.5. More preferably, H/W is 0.3 or less. The height H of the sealing member 30 is defined as an interval in the optical axis L direction from the mounting surface of the base body 10 to the highest part of the sealing member 30 . The width W is based on the shape of the bottom surface of the sealing member 30 . In the case where the bottom face is circular, it is the diameter of the circle, and in the case of other shapes, it is defined as the shortest width of the bottom face. For example, when the outer shape when viewed from above is elliptical, the width of the bottom face has a long diameter and a short diameter, but the short diameter is the width W.

When the sealing member 30 has this shape, the light emitted from the light emitting element 21 is refracted at the interface between the sealing member 30 and the air, so that the light distribution can be further widened.

As the material of the sealing member 30, a translucent resin such as an epoxy resin, a silicone resin, or a resin obtained by mixing them, glass, or the like can be used. Among these, it is preferable to select a silicone resin from the viewpoint of light resistance and ease of molding.

The sealing member 30 may contain a wavelength conversion material and a diffusion agent for diffusing light from the light emitting element 21 . In addition, a colorant may be included so as to correspond to the light emission color of the light emitting element. It is preferable that these wavelength conversion materials, diffusion materials, colorants, etc. are contained in the sealing member 30 in an amount sufficient to control light distribution depending on the outer shape of the sealing member 30 . Further, in order to suppress the influence on the light distribution characteristics, the particle size of the material to be incorporated is preferably 0.2 μm or less. In addition, in this specification, a particle diameter means the thing of an average particle diameter (median diameter), and the value of an average particle diameter can be measured by the laser diffraction method.

[Light emission and effect of light emitting device 101]

In the light emitting device 101 , a dielectric multilayer film 22 is provided on the upper surface 21a of the light emitting element 21 . With this configuration, part of the light emitted from the upper surface 21a of the light emitting element 21 is reflected by the dielectric multilayer film 22, returns to the light emitting element 21, and passes through the side surface 21c of the light emitting element 21. go out As a result, the amount of light emitted from the upper surface of the light emitting element 21 is reduced, and the luminance above the light emitting element 21 is reduced, resulting in a case where a backlight or the like is configured using the light emitting device 101. Suppresses luminance unevenness.

However, according to the study of the inventors of the present application, when a dielectric multilayer film is provided on the upper surface of the light emitting device and a diffusion plate or the like is disposed on the emission side of the light emitting device to form a backlight, the distance between the diffusion plate and the light emitting element becomes shorter. , it was found that the luminance was lowered than the surrounding area in the vicinity of the upper side of the light emitting element. Fig. 3 shows light emission viewed through a diffuser plate with a general dielectric multilayer film that does not have the spectral characteristics of the dielectric multilayer film 22 provided on the upper surface of the light emitting element. This is because the distance OD (shown in FIG. 5) between the diffusion plate and the light emitting element is shortened, so that light emitted vertically from the upper surface of the light emitting element mainly enters the upper side of the light emitting element, is reflected by the dielectric multilayer film, and emits light. It is considered that this is because light emitted from the side surface of the element becomes difficult to enter. In other words, if the dielectric multilayer film is provided on the upper surface 21a of the light emitting element 21, the luminance of the area around the light emitting element is higher than that of the area above the light emitting element, resulting in luminance unevenness. When the reflectance of the dielectric multilayer film is lowered, the luminance of the region above the light emitting element rises, but the luminance of the region around it also rises, so the luminance unevenness is not significantly reduced.

In the light emitting device 101 of the present disclosure, the incidence angle dependence of the spectral reflection characteristics of the dielectric multilayer film is used to suppress the above-mentioned luminance unevenness. In general, the spectral reflection characteristics of a dielectric multilayer film are different when light enters the dielectric multilayer film perpendicularly and obliquely. Compared to the case where the light is incident vertically, the optical path length becomes longer when the light is incident obliquely, so the reflected wavelength band shifts to the shorter wavelength side. This feature is also called blue shift. 4 is a diagram schematically showing an example of spectral reflection characteristics of a dielectric multilayer film, solid lines represent spectral reflection characteristics for normally incident light, and broken lines represent spectral reflection characteristics for light incident from a direction inclined at 45° from the vertical direction. exhibits reflective properties. The reflection wavelength band for normally incident light is about 430 nm to 550 nm, but the reflection wavelength band for 45° inclined incident light is 350 nm to 500 nm. The shift amount of the spectral reflection characteristics to the shorter wavelength side is about 40 nm at about 400 nm and about 80 nm at about 700 nm.

As shown in Fig. 4, in a typical dielectric multilayer film, the spectral reflectance in the reflection wavelength band is substantially constant. However, as shown in FIG. 2 , the dielectric multilayer film 22 used in the light emitting device 101 of the present disclosure has different spectral reflectances in the reflection wavelength band in the emission peak wavelength region R _E and the region R E . _L ) has spectral reflectance characteristics including Accordingly, even light having the same peak wavelength can be reflected with different spectral reflectances depending on the incident angle.

2 schematically shows an example of reflectance characteristics of the dielectric multilayer film 22 in the light emitting device 101 of the present embodiment. The solid line represents the spectral reflection characteristics of normally incident light, and the broken line represents the reflection characteristics for light incident from a direction inclined at 45° from the vertical direction. In the example shown in FIG. 2 , the emission peak wavelength of the light emitting element 21 is about 450 nm, and the emission peak wavelength region (R _E ) is 430 nm to 470 nm. Further, the region R _L is 480 nm to 520 nm. In addition, the spectral reflectance in the emission peak wavelength region (R _E ) is about 75%, and the spectral reflectance in the region (R _L ) is about 92%. That is, light perpendicularly incident on the dielectric multilayer film 22 is reflected with a spectral reflectance of about 75%, but light incident obliquely on the dielectric multilayer film 22 is reflected with a spectral reflectance of about 92% at maximum.

As a result of detailed examination, for example, in the case of the light emitting element 21 that emits blue light, setting the shift amount to 50 nm increases the luminance of the region above the light emitting element 21 and further increases the brightness of the region around it. It was found that the luminance unevenness can be efficiently reduced by lowering the luminance.

FIG. 5 schematically shows the propagation of light when the light emitted from the light emitting device 101 is made incident on the diffusion plate 51 . When the distance OD between the light emitting element 21 and the diffusion plate 51 is short, as shown in FIG. 5 , in the region 51a above the light emitting element 21 in the diffusion plate 51, mainly, The light 23a that vertically enters the dielectric multilayer film 22 from the upper surface 21a of the light emitting element 21 and passes through is incident. In contrast, light 23b that obliquely enters and passes through the dielectric multilayer film 22 and light 23e that exits from the side surface 21c enter the region 51b around the region 51a. As described above, when passing through the dielectric multilayer film 22, the spectral reflectance of the light 23a is 75%, whereas the spectral reflectance of the light 23b is 92%. Therefore, since the ratio of the light 23b reaching the diffusion plate 51 is greater than that of the light 23a, the luminance of the region 51b in the diffusion plate 51 is relatively increased, and the luminance of the region 51a is increased. can lower As a result, the light emitted from the light emitting element 21 provided with the multilayer dielectric film 22 has a bat wing-type light distribution characteristic in which the difference in luminance between the center and the outer periphery is small in the plane including the optical axis L. can In a broad sense, the light distribution characteristic of the bat wing type is defined as an emission intensity distribution in which the emission intensity is strong at an angle where the absolute value of the light distribution angle is greater than 0 ° with the optical axis L at 0 °. In particular, in a narrow sense, it is defined as the emission intensity distribution in which the emission intensity is the strongest in the vicinity of 45° to 90°.

The light emitting device 101 reduces the luminance of the region above the light emitting element 21 and also reduces luminance unevenness by including the dielectric multilayer film 22 described above. This means that the light emitted from the light emitting device 101 is wide-distributed, that is, a large amount of light is emitted even at a low angle. For example, 25% or more of the total amount of light emitted from the light emitting device 101 of the present disclosure may be emitted at an elevation angle of less than 20 degrees with respect to the upper surface of the base 10 .

In addition, by configuring the outer shape of the sealing member 30 as a convex curved surface and setting the height-to-width ratio H/W to less than 0.5, the light emitted from the light emitting element 21 can be light-distributed. For example, if the ratio H/W of the height H to the width W of the sealing member 30 is set to 0.3 or less, 40% or more of the total amount of light emitted from the light emitting device 101 is emitted from the body 10. It is possible to emit at an elevation angle of less than 20 degrees with respect to the upper surface. In this way, with these two configurations, it is possible to obtain desired light distribution characteristics without using a secondary lens. That is, since the luminance above the light emitting element 21 can be reduced by providing the dielectric multilayer film 22, the sealing member 30 mainly has a function of wide-distributing the light from the light emitting element 21. It is good to have For this reason, significant miniaturization of the sealing member 30 having a lens function can be realized. This makes it possible to realize a thin backlight module (light emitting module) with reduced luminance unevenness by using the light emitting device 101 .

In a conventional light emitting device, the function of reducing the luminance above the light emitting element and the function of light distribution were given to the sealing member. For this reason, for example, a sealing member that has a relatively large external shape and functions also as a secondary lens is required.

(Second Embodiment)

6A is a schematic diagram showing a cross-sectional structure of the light emitting module 102 of the present embodiment. The light emitting module 102 includes a light transmitting laminate 50 and an integrated light emitting device 103 . 6B is a top view of the integrated light emitting device 103 .

The integrated type light emitting device 103 includes a base 10, a plurality of light emitting elements 21 arranged on the base 10, and a dielectric multilayer film 22 provided on the upper surface of each light emitting element 21. The structures of the base body 10, the light emitting element 21 and the dielectric multilayer film 22 and the relationship between these components are as described in the first embodiment.

The plurality of light emitting elements 21 are arranged one-dimensionally or two-dimensionally on the upper surface 11a of the base body 10 . In this embodiment, the plurality of light emitting elements 21 are two-dimensionally arranged along two orthogonal directions, that is, the x direction and the y direction, and the arrangement pitch px in the x direction and the arrangement pitch py in the y direction are the same . However, the arrangement direction is not limited to this. The pitches in the x direction and the y direction may be different, and the two directions of the array need not be orthogonal. Also, the array pitch is not limited to equal intervals, and may be unequal intervals. For example, the light emitting elements 21 may be arranged so that the intervals from the center of the body 10 become wider toward the periphery.

The integrated type light emitting device 103 may include a plurality of light reflection members 15 positioned between the light emitting elements 21 . The light reflecting member 15 includes wall portions 15ax and 15ay and a bottom portion 15b. As shown in FIG. 6B, a wall portion 15ay extending in the y direction is disposed between two light emitting elements 21 adjacent in the x direction, and between two light emitting elements 21 adjacent in the y direction in the x direction. An extending wall portion 15ax is disposed. For this reason, each light emitting element 21 is surrounded by two wall portions 15ax extending in the x direction and two wall portions 15ay extending in the y direction. A bottom portion 15b is located in a region 15r surrounded by two wall portions 15ax and two wall portions 15ay. In this embodiment, since the arrangement pitches of the light emitting elements 21 in the x direction and the y direction are the same, the outer shape of the bottom portion 15b is a square. A through hole 15e is provided at the center of the bottom portion 15b, and the bottom portion 15b is positioned on the insulating layer 13 so that the light emitting element 21 is positioned in the through hole 15e. There is no particular restriction on the shape and size of the through hole 15e, as long as the shape and size allow the light emitting element 21 to be positioned therein. The outer edge of the through hole 15e is located near the light emitting element 21 so that the light from the light emitting element 21 can also be reflected at the bottom 15b, that is, when viewed from above, the through hole 15e ) and the light emitting element 21 is preferably narrower.

As shown in Fig. 1, in the yz cross section, the wall portion 15ax includes a pair of inclined surfaces 15s extending in the x direction. Each of the pair of inclined surfaces 15s is connected to each other on one side of two sides extending in the x direction, and constitutes a top 15c. The other side is connected to the bottom part 15b located in the adjacent two area|region 15r, respectively. Similarly, the wall portion 15ay extending in the y direction includes a pair of inclined surfaces 15t extending in the y direction. Each of the pair of inclined surfaces 15t is connected to each other on one side of two sides extending in the y direction, and constitutes the top 15c. The other side is connected to the bottom part 15b located in the adjacent two area|region 15r, respectively.

A light emitting space 17 having an opening is formed by the bottom portion 15b, the two wall portions 15ax and the two wall portions 15ay. In Fig. 6B, light emitting spaces 17 arranged in 3 rows and 3 columns are shown. The pair of inclined surfaces 15s and the pair of inclined surfaces 15t face the opening of the light emitting space 17 .

The light reflecting member 15 has a light reflecting property, and reflects the light emitted from the light emitting element 21 toward the opening of the light emitting space 17 by the inclined surfaces 15s and 15t of the wall portions 15ax and 15ay. . In addition, light incident on the bottom portion 15b is also reflected toward the opening of the light emitting space 17 . In this way, the light emitted from the light emitting element 21 can be efficiently entered into the light-transmitting laminate 50 .

The light emitting space 17 partitioned by the light reflection member 15 becomes the smallest unit of the light emitting space when the plurality of light emitting elements 21 are independently driven. In addition, when the light emitting device 101 as a surface light emitting source is viewed from the upper surface of the light-transmitting laminate 50, it becomes the minimum unit area for local dimming. When the plurality of light emitting elements 21 are driven independently, a light emitting device capable of being driven by local dimming in units of the smallest light emitting space is realized. When a plurality of adjacent light emitting elements 21 are simultaneously driven and driven so as to synchronize ON/OFF timings, driving by local dimming in a larger unit becomes possible.

The light reflection member 15 may be molded using, for example, a resin containing a reflector made of metal oxide particles such as titanium oxide, aluminum oxide, and silicon oxide, or may be molded using a resin that does not contain a reflector. After that, a reflector may be provided on the surface. It is preferable that the reflectance of the light reflection member 15 with respect to the light emitted from the light emitting element 21 is 70% or more, for example.

The light reflection member 15 can be formed by molding using a mold or stereolithography. As a molding method using a mold, molding methods such as injection molding, extrusion molding, compression molding, vacuum molding, pressure molding, and press molding can be used. For example, the light reflection member 15 in which the bottom portion 15b and the wall portions 15ax and 15ay are integrally formed can be obtained by vacuum forming using a reflection sheet made of PET or the like. The thickness of the reflective sheet is, for example, 100 μm to 500 μm.

The lower surface of the bottom portion 15b of the light reflection member 15 and the upper surface of the insulating layer 13 are fixed with an adhesive member or the like. The insulating layer 13 exposed through the through hole 15e preferably has light reflectivity. It is preferable to dispose an adhesive member around the through hole 15e so that light emitted from the light emitting element 21 does not enter between the insulating layer 13 and the light reflection member 15 . For example, it is preferable to arrange an adhesive member in a ring shape along the periphery of the through hole 15e. The adhesive member may be a double-sided tape, a hot melt type adhesive sheet, or an adhesive liquid of a thermosetting resin or a thermoplastic resin. It is preferable that these adhesive members have high flame retardancy. In addition, you may be fixed with other coupling members, such as a screw and a pin, not an adhesive member.

Each region Ru surrounded by the plurality of light reflection members 15 can be regarded as one light emitting device 101 having a light emitting element 21 . That is, the integrated type light emitting device 103 includes a plurality of light emitting devices 101 arranged at a pitch Px and a pitch Py in the x direction and the y direction.

The height HR of the light reflection member 15 is preferably 0.3 times or less, more preferably 0.2 times or less of the arrangement pitch of the light emitting devices 101 . In the case where the light emitting devices 101 are arranged two-dimensionally, it is the shorter pitch among the pitches in the two directions. In this embodiment, since the arrangement pitch px in the x direction and the arrangement pitch py in the y direction are the same, the height HR is 0.3 times or less of Px and Py, that is, HR≤0.3Px or HR≤0.3Py. When the height HR of the light reflection member 15 satisfies this condition, the distance between the light-transmitting laminate 50 and the integrated light-emitting device 103 can be shortened, thereby realizing a thin light-emitting module.

The light transmission laminate 50 is disposed on the light extraction surface side of each light emitting device 101 of the integrated type light emitting device 103, that is, on the upper surface side of the light emitting element 21 of the base body 10. The light transmitting laminate 50 may be in contact with the light reflecting member 15 or may be spaced apart from each other. The light transmission laminate 50 includes a diffusion plate 51 and a wavelength conversion member 52 .

The diffuser plate 51 diffuses and transmits incident light. The diffusion plate 51 is made of, for example, a material that absorbs little visible light, such as polycarbonate resin, polystyrene resin, acrylic resin, or polyethylene resin. A structure for diffusing light is provided in the diffusion plate 51 by providing irregularities on the surface of the diffusion plate 51 or dispersing materials having different refractive indices in the diffusion plate 51 . As the diffuser plate 51, those commercially available under names such as a light diffusion sheet and a diffuser film may be used.

The wavelength conversion member 52 is located on a surface opposite to the surface facing the light emitting device 101 among the two main surfaces of the diffusion plate 51 . The wavelength conversion member 52 absorbs part of the light emitted from the light emitting device 101 and emits light having a wavelength different from that of the light emitted from the light emitting device 101 .

Since the wavelength conversion member 52 is separated from the light emitting element 21 of the light emitting device 101, a light conversion material that is difficult to use in the vicinity of the light emitting element 21 and has poor resistance to heat or light intensity can also be used. can This makes it possible to improve the performance of the light emitting device 101 as a backlight. The wavelength conversion member 52 has a sheet shape or layer shape and includes a wavelength conversion material.

The wavelength conversion material may be, for example, a cerium-activated yttrium-aluminum-garnet (YAG)-based phosphor, a cerium-activated lutetium-aluminum-garnet (LAG), and a nitrogen-containing aluminosilicate activated with europium and/or chromium. nitride-based phosphors such as calcium (CaO-Al ₂ O ₃ -SiO ₂ )-based phosphors, europium-activated silicate ((Sr, Ba) ₂ SiO ₄ )-based phosphors, β-sialon phosphors, CASN-based or SCASN-based phosphors, KSF-based phosphors (K ₂ SiF ₆ :Mn), sulfide-based phosphors, and the like are included. As phosphors other than these phosphors, phosphors having the same performance, action, and effect can also be used.

In addition, the wavelength conversion member 52 may contain, for example, a so-called nanocrystal or a light emitting material called a quantum dot. As such materials, semiconductor materials can be used, for example, group II-VI, group III-V, group IV-VI semiconductors, specifically, CdSe, core-shell type CdSxSe _{1 -x} /ZnS, nano such as GaP size of highly dispersed particles.

According to the light emitting module 102, even if it has a thin structure, it is possible to suppress luminance unevenness.

(Third Embodiment)

7A is a schematic diagram showing a cross-sectional structure of the backlight 104 of the present embodiment. The backlight 104 includes a case 60 and a light emitting module 102 .

The case 60 includes a bottom portion 60A and a side portion 60B. The bottom portion 60A has a main surface 60m for supporting the integrated type light emitting device 103 of the light emitting module 102, and, for example, the base material 11 of the base body 10 is in contact with the main surface 60m. there is. The side portion 60B is disposed on the bottom portion 60A so as to surround the integrated light emitting device 103 supported on the main surface 60m, and the first plane 60a, the second plane 60b, and the side surface ( 60c). In this embodiment, since the integrated light emitting device 103 and the light-transmitting laminate 50 have a rectangular shape when viewed from a plan view, the side portions 60B are disposed at four positions corresponding to the four sides of the rectangle. That is, the case has four side portions 60B corresponding to the four sides of the rectangle, and each side portion 60B forms a first plane 60a, a second plane 60b, and a side surface 60c. Have.

The side portion 60B supports the end of the light-transmissive stack 50 on the first plane 60a, whereby the light-transmitting stack 50 is configured to support each light emitting device of the integrated type light emitting device 103 ( 101), that is, on the upper surface side of the light emitting element 21 of the base body 10. As described above, the light-transmitting laminate 50 may be in contact with the light reflecting member 15 or may be spaced apart from each other.

The second flat surface 60b is further away from the main surface 60m of the bottom portion 60A than the first flat surface 60a in the z-axis direction. The second flat surface 60b contacts an end portion of a display panel such as a liquid crystal display panel on which the backlight 104 is mounted, and thereby the backlight 104 is mounted on the display panel.

The side surface 60c is located between the first plane 60a and the second plane 60b in the z-axis direction, and faces the side surface (end section) 50t of the light-transmissive laminate 50. . As described above, when the laminate 50 has a rectangular shape, the side surface 60c of the case 60 faces the four side surfaces 50t of the laminate 50, respectively, and the laminate 50 ) is surrounded by four sides (50t).

It is preferable that the backlight 104 is equipped with the reflective film 62 supported by the case 60. Specifically, it is preferable that the reflective film 62 is provided as a reflective member on the side surface 60c of the case 60, and the reflective film 62 faces the side surface 50t. The reflective film 62 preferably has a reflective characteristic of diffusely reflecting incident light. The reflective film 62 can be formed of the same material as the material of the insulating layer 13, for example. Specifically, a material obtained by containing a white filler in a resin such as epoxy, silicone, modified silicone, urethane resin, oxetane resin, acrylic, polycarbonate, or polyimide can be used as the reflective film 62 . There may be a gap between the reflective film 62 and the side surface 50t of the laminate 50, or the reflective film 62 may be in contact with the side surface 50t without a gap.

In the backlight 104, the reflective film 62 reflects light emitted from the side surface 50t of the light-transmitting laminate 50 and returns it to the light-transmitting laminate 50 from the side surface 50t. As a result, the light that has not undergone wavelength conversion from the vicinity of the outer periphery of the side surface 50t of the light projector 50 or the upper surface 50a of the light projector 50 at a higher rate than that of the vicinity of the center of the upper surface 50a. It is possible to increase the uniformity of the light emitted from the backlight 104 by suppressing a decrease in the uniformity of the emitted light, such as a blue appearance, compared to the central portion of the upper surface 50a. Therefore, it is possible to realize a thin backlight with high uniformity of emitted light.

In addition to the diffusion plate 51 and the wavelength conversion layer 52, the backlight 104 may include other layers such as a prism sheet and a reflective layer in the light-transmissive laminate 50. For example, another light-transmitting layer 53 such as a prism sheet or a reflective polarizing sheet may be provided to increase the component of light incident perpendicularly to the display panel. When the light-transmitting laminate 50 includes the light-transmitting layer 53 having such optical characteristics, the light propagating through the light-transmitting layer 53 and exiting from the side surface 50t of the light-transmitting laminate 50 By increasing, there is a possibility that the uniformity of light in the vicinity of the outer periphery of the upper surface 50a described above is lowered. According to the backlight 104, even in this case, it is possible to improve the uniformity of the light emitted from the backlight 104 by the above-described action of the reflective film 62.

As shown in FIG. 7B , instead of providing the reflective film 62 on the side surface 60c of the case 60, the backlight 104 is provided on the side surface 60c and the side surface 50t of the light-transmitting laminate 50. ), you may be provided with the reflecting plate 63 supported by the 1st flat surface 60a as a reflecting member. The reflector 63 may be entirely made of a reflective material, or may have a structure in which a reflective film is formed on the surface of a non-reflective substrate. The reflector 63 faces the side surface 50t of the light-transmissive laminate 50 . Even when the backlight 104 includes the reflector 63, it is possible to increase the uniformity of emitted light as described above.

As described above, in the backlight of this embodiment, a light-transmitting laminate including a light-emitting module, the wavelength conversion member and the dielectric multilayer film, an integrated type light-emitting device of the light-emitting module, and the light-transmitting laminate are arranged at a predetermined interval. and a case supported by the case, and a reflective member supported by the case and disposed to face a side surface of the light-transmitting laminate.

Another backlight of this embodiment includes a light-transmitting laminate including a light emitting module, the wavelength conversion member and the dielectric multilayer film, and a reflective member disposed to face a side surface of the light-transmitting laminate.

The light emitting device, integrated type light emitting device, and light emitting module of the present disclosure can be used for various light sources such as a backlight of a liquid crystal display and a lighting fixture.

10: gas
11: registration
11a: top surface
12: conductor wiring
13: insulating layer
14: insulation member
15: light reflection member
17: luminous space
21: light emitting element
21a: upper surface
21c: side
22: dielectric multilayer film
23: connection member
24: underfill member
30: sealing member
50: light transmission laminate
51: diffusion plate
52: wavelength conversion member
60: case
60A: bottom
60B: side
60a: first plane
60b: second plane
60c: side
62: Reflective
63: reflector
101: light emitting device
102: light emitting module
103 integrated light emitting device
104: backlight

Claims (13)

As a light emitting device,
a body having conductor wiring;
a light emitting element disposed on the body so as to be electrically connected to the conductor wiring;
A dielectric multilayer film provided on the upper surface of the light emitting element
to provide,
The dielectric multilayer film has a spectral reflectance in a region on the 50 nm long wavelength side greater than the emission peak wavelength region of the light emitting element by 10% or more with respect to the spectral reflectance in the emission peak wavelength region of the light emitting element. With respect to the light of the emission peak wavelength from the light emitting element, the light incident obliquely to the dielectric multilayer film is reflected with a higher spectral reflectance than the light incident vertically to the dielectric multilayer film.
light emitting device. According to claim 1,
The light emitting device, wherein the spectral reflectance in the emission peak wavelength region of the light emitting element is 70% or more and 95% or less. According to claim 1 or 2,
The light emitting device, wherein a reflection wavelength band at normal incidence of the dielectric multilayer film includes a peak emission wavelength of the light emitting element, and a longer wavelength side than the emission peak wavelength is wider than a shorter wavelength side. According to claim 1 or 2,
The light emitting device, wherein 25% or more of the total amount of light emitted from the light emitting device is emitted at an elevation angle of less than 20 degrees with respect to the upper surface of the base body. According to claim 1 or 2,
Further comprising a sealing member covering the light emitting element and the dielectric multilayer film,
The light emitting device, wherein the ratio H/W of the height H to the width W of the sealing member is smaller than 0.5. According to claim 5,
The light emitting device, wherein 40% or more of the total amount of light emitted from the light emitting device is emitted at an elevation angle of less than 20 degrees with respect to the upper surface of the base body. According to claim 6,
The light emitting device, wherein the ratio H/W of the height H to the width W of the sealing member is 0.3 or less. According to claim 1 or 2,
The light emitting device is flip-chip mounted on the base body. As an integrated light emitting device,
A plurality of light-emitting devices according to claim 1 or 2;
A plurality of light reflecting members respectively disposed between the plurality of light emitting devices
An integrated type light emitting device comprising: According to claim 9,
The integrated type light emitting device of claim 1 , wherein a height of the light reflection member is 0.3 times or less of a distance between the light emitting devices. According to claim 9,
The integrated light emitting device of claim 1 , wherein a height of the light reflection member is 0.2 times or less of a distance between the light emitting devices. As a light emitting module,
The light emitting device according to claim 1 or 2;
A wavelength conversion member located on the light extraction surface side of the light emitting device, absorbing a part of the light of the light emitting element and emitting light of a wavelength different from that of the light emitting element.
A light emitting module having a. As a light emitting module,
The integrated type light emitting device according to claim 9;
A wavelength conversion member located on the light extraction surface side of the light emitting device, absorbing a part of the light of the light emitting element and emitting light of a wavelength different from that of the light emitting element.
A light emitting module having a.

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